JPH03213598A - Production of coated paper for offset - Google Patents

Abstract

PURPOSE:To obtain the title paper having one side suitable for heat setoff type ink and the other suitable for cold setoff ink by coating one side of mechanical pulp-containing base paper with pigment-containing coating film to increase gloss degree of this side. CONSTITUTION:One side (side A) of base paper containing mechanical pulp such as pressure stone ground pulp is coated with a pigment-containing coating film composition, the other side (side B) is not coated, the side A coated under a condition of glazer is selectively treated so as to increase gloss degree so that one side can be subjected to monochromatic printing and the other side to high-quality process printing because the side A of the coated paper is suitable for offset process printing and the uncoated side B opposite to the side A is fitting to permeable dry type ink.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing coated paper for offset printing, and is particularly suitable for printing on one side using heat set-off type ink when printing on a rotary offset press. , the other side relates to a method for producing coated paper for off-line export, which is suitable for printing using cold set-off type inks, so that different types of inks can be used on the front and back sides, or printing can be performed using different printing methods.

(Prior Art) In recent years, the demand for coated printing papers with excellent print finish and clarity has increased significantly, and their uses have also expanded in a wide variety of fields.

There is a particularly strong trend toward colorization and visualization, and this trend extends to newspaper inserts that print in large numbers.
The operating rate of the rotary presses that print these items is also increasing.

Generally, multicolor printing on coated paper for printing requires clarity, so oxidative polymerization type ink is used, and a heat-set type rotary press equipped with an afterdryer is used, but as the operating rate increases, Printing shops equipped with such rotary presses are becoming increasingly unavailable. Also, on the other hand,
There is a need for high-quality multicolor printing on one side, and general monochrome printing on the other side.

The multicolor printing surface uses oxidative polymerization type ink, and good print quality can be obtained by printing on a heat-setting/soto type rotary press equipped with an afterdryer. However, for the opposite side, it is common to use penetrating ink due to the required printing quality or equipment considerations. In particular, when this printing is performed using newspaper printing equipment, single-color printing is performed before multi-color surfaces, and multi-color printing is performed without passing through a drying device, so the ink on the opposite side is not completely dried. Ink set is insufficient.

Therefore, during the binding or folding and transportation process, the printed surface of the printed material is rubbed and damaged before it reaches the user. In addition, a serious problem arises in that the stripped ink stains the opposite surface that overlaps the printed surface.

Furthermore, in the printing process, the ink drying properties are the same on both sides of coated paper for offset and sotho, so if penetrating drying ink is used to print on the side that does not use an after-dryer, the ink on the printed side will dry. ``Set-off'' occurs on the impression cylinder of the printing press, causing a problem called ``doubling'' in which the printed surface gradually shifts.

(Problems to be Solved by the Invention) High-quality multicolor printing on only one side has been practiced for a long time, and many types of paper with different front and back sides have been commercially available. These include information recording papers for heat-sensitive, pressure-sensitive, and non-impact printers, miscellaneous papers such as photographic paper, magnetic recording paper, photosensitive base paper, copying paper, special papers, and glossy paper. Wrapping paper such as kraft, card, paperboard, corrugated pole etc. may be mentioned.

However, these are not sheets of paper that actively increase the difference between the front and back sides for the purpose of double-sided printing. For the purpose of obtaining beautiful printed matter, coated paper in which a coating composition is coated and dried and then treated with a glossing device such as a super calender is suitable. It is common practice to print with hard (high viscosity) ink and force dry it with an afterdryer.

Gloss coated paper has a dense paper surface and high smoothness, so ink can easily adhere evenly, and because the paper surface is dense, ink does not sink into the paper, so it is effective for obtaining clearer printed matter. It is considered to be a target. The more viscous the ink, the more ink can be transferred to the paper, making it possible to obtain thicker printed matter.

However, glossy coated paper is suitable for producing beautiful multicolor prints if a forced dryer is used as described above, but the ink is hardly dry from the moment it is printed until it passes through the forced dryer. If there are other printing processes, paper transport equipment, etc. in the intermediate process, ink may adhere to those parts and eventually stain the printing surface and the printing machine itself. Occur.

Furthermore, in order to prevent such staining troubles in the pre-process of forced drying, there is a method of increasing the ink absorption speed and absorption power of the paper, and using a penetrating type of ink.

However, in both letterpress printing and offset printing, which are printing methods that use penetrating drying inks, unless the ink absorption speed and absorption capacity are increased to speed up the drying process, there will be double printing and printed matter. Set-off, ink removal due to rubbing of printed surfaces or paper and hands (rub-off)
This will cause a serious problem.

On the other hand, when applying a coating composition of 3 to 15 g/m2 in order to improve the printing quality of the surface to be printed in multiple colors, the opposite side is usually coated with approximately the same amount of the coating composition. Furthermore, it is common to apply calendering or supercalendering to give the paper surface smoothness and gloss, but in this case, the opposite side also becomes smooth and glossy.
As a result, the ink usually becomes difficult to penetrate and dry.

For the above reasons, with existing technologies and their combinations, one side has the suitability for offset printing on a par with conventional coated paper and slightly coated paper, and the other side has the suitability for printing with penetrating drying inks. There was no such paper available, and there was a strong demand for a new product like this.

Therefore, in the present invention, one side uses oxidative polymerization type ink to produce a beautiful multicolor printing effect using a heat set type printing machine, and the other side uses penetrating drying type ink to perform monochrome printing using a cold set type printing machine. An object of the present invention is to provide a coated paper capable of simultaneous printing on both sides and a method for producing the same.

(Means for Solving the Problems) The present invention provides a pigment coating composition A for base paper containing at least one type of mechanical pulp such as pressurized stone ground pulp, stone ground pulp, refiner ground pulp, and thermomechanical pulp. Absolutely dry coating amount on the surface only is 3.5
g/m2 or more, and coated the A side with JtS-P8.
The glossiness measured with 142 is 20% or more, and the B side is printed with newspaper off-ring ink (equivalent to TV = 3 to 4) using an RI printing machine.
One minute after printing using a penetrating drying type offset ink with a printing density of 1.0±0.1 using a courser densitometer, the printed surface had a whiteness of 82±1.5% and a gloss of 62. ±
When 8% commercially available A2 coated paper is stacked and pressed together with a pressure of 10mm nip width, the value (setoff value) measured with a Koser densitometer of ink transfer to commercially available A2 coated paper is 0.28.
An offset characterized in that the A side is given properties suitable for heat set-off printing and the B side is given properties suitable for printing using penetrating drying ink by performing a glossing process as shown below. This is a method for producing coated paper for paper.

In the present invention, a coating composition containing a pigment is applied to a base paper for coating.
It is essential to coat the surface, dry it, and then process it using a polishing device such as a super calender, rough 1-calender, or gloss calender. Since the present invention has the above-described structure, the A side is required to have high gloss in order to obtain beautiful multicolor printing, and the B side is required to have ink absorption (oil absorption) represented by the ink absorption speed and absorption power. )is important.

However, these two aptitudes have antinomic elements, and if you increase the amount of coating on the A side and strengthen the polishing conditions such as super calender, there will be differences in the degree of A.
Although the glossiness of both the side and the B side is improved, the surface becomes denser and the ink absorbency deteriorates. On the other hand, if side B is not coated, the amount of coating on side A is reduced, and the conditions for polishing with a super calender are relaxed, the ink absorption of both side A and B will improve, and the gloss will increase instead. descend.

As a result of various studies to solve this problem, the present invention has overcome this difficulty by adopting the following configuration.

That is, (1) The base paper is made by selecting a pulp that has excellent ink absorption properties and has a large effect on gloss when glossing the paper after coating.

(2) A to differentiate the characteristics of side A and side B of coated paper
Coating is applied only to side B, and side B is left uncoated, so that even if the polishing treatment conditions are relatively relaxed, the desired glossiness of side A can be obtained, and side B is left uncoated. The synergistic effect of this and the relaxation of the polishing treatment conditions further reduced the density of the surface, making it possible to prevent deterioration of ink absorbency.

(3) Regarding the glossing treatment conditions, in a device that combines a soft roll and a metal roll such as a super calender, the gloss of the paper surface in contact with the metal roll improves and the density of the surface increases; Unlike the surface in contact with a metal roll, the increase in gloss and density of the paper surface in contact with the surface is small, so in the present invention, the number of times that the A side is in contact with the metal roll is increased, and the number of times that the B side is in contact with the metal roll is either zero or I decided to perform the polishing process so that the number of times the polishing process would be significantly reduced.

The base paper for coating used in the present invention is pressurized 7, )-ground pulp (PGW), stone ground pulp (
Contains at least one kind of mechanical pulp such as Refiner Glandhalp (GP), Refiner Glandhalp (RGP), and Thermomechanical Pulp (TMP), preferably 20 to 70% by weight of mechanical pulp, and more preferably PGW. It contains. This PGW has no binding in its fibers and is flexible, and the fiber length contains many intermediate fibers between GP and TMP, and is fibrillated, so by using this pulp, the smoothness and surface roughness of the base paper can be improved. will improve.

This improves coating unevenness during coating, improves the gloss of coating 1 paper, and improves ink receptivity during printing, making it possible to create beautiful and good-looking printed materials. It is.

The fiber shape of TMP is that the chips softened by press steaming are pressurized and refined as they are, so they are defibrated well, so there is less fiber cutting and binding fibers, and good long fibers can be obtained. For this reason, TMP
When it is included in the base paper, the base paper generally has a low density and is bulky, so the oil absorbency is improved and the ink set-off value can be reduced.

Other GP and RGP can also reflect the characteristics of pulp in the base paper, and deinked waste paper pulp (DIP) can also be used.

When these mechanical pulps are contained in an amount of 70% by weight or more, printability improves, but the paper strength represented by tensile strength, tear strength, and bursting strength decreases, and if the content is less than 20% by weight, printability becomes difficult to achieve. This is inconvenient for the purposes of the present invention.

2 As other pulps, softwood and hardwood bleached and semi-bleached pulps can be used together with mechanical pulps and DIP.

The base paper for coating used in the present invention is made of the above-mentioned pulp as a raw material and made into acidic paper using a band, rosin sizing agent and other auxiliary agents in a conventionally known paper machine, or neutral paper without using a band as necessary. If desired, a filler may be added thereto for paper making.

The pigments in the coating composition used in the present invention are not particularly limited, and include kaolin, clay, heavy calcium carbonate, light calcium carbonate, aluminum hydroxide, zatin white, titanium dioxide, calcium sulfite, and zinc sulfate. Ordinary pigments for coated paper such as , plastic pigments, etc. are appropriately selected and blended according to the properties of each pigment.

In addition, for adhesives, casein, soy protein, yeast protein,
Starch and oxidized starch, esterified starch, etherified starch,
Modified starch such as cationized starch, natural adhesives such as cellulose derivatives, conjugated diene copolymer latex such as styrene/butadiene copolymer, methyl methacrylate/butadiene copolymer, polymers of acrylic and/or methacrylate esters, etc. Synthetic resin adhesives such as alkali-insensitive or alkali-IJ g-responsive synthetic resin emulsions, such as acrylic polymer latex such as polymers or copolymers, and vinyl acetate copolymer latex such as ethylene-vinyl acetate copolymer. One or more conventional coated paper adhesives may be used depending on the paper quality targeted by the present invention. The amount of adhesive to be blended is generally in the range of 5 to 20 parts by weight per 100 parts by weight of pigment.

In addition, various auxiliary agents, such as dispersants, flow modifiers, antifoaming agents, preservatives, lubricants, waterproofing agents, water retention agents, and dyes, which are generally incorporated into coating compositions, may be appropriately incorporated as necessary. The formulations to obtain the target surface strength, ink adhesion, white paper gloss, gloss after printing, smoothness, whiteness, opacity, etc., and the formulations to prevent the decrease in vapor permeability of the coating layer are as described above. This is done by changing the types and amounts of pigments, adhesives, and auxiliary chemicals. There are no particular limitations on the coating method, and air knife coaters, roll coaters, paddle and inverter type blade coaters with beveled and bent blades, and various blade coaters such as bill blades and twin blades can be used. Various conventional coating devices can be used as appropriate.

In the present invention, the coating composition is applied only to side A at a rate of 3.5 g/m
It is essential that the coating amount be 2 or more.

At 3.5 g/m2 or less, if the processing conditions of the polishing device such as a super calender are changed in an attempt to raise the glossiness of side A to the desired level 2, the density of side B will increase and the ink absorption will deteriorate. This will cause set-off trouble. On the other hand, if the processing conditions of the polishing device are applied to improve the ink absorption of the B side and eliminate the set-off trouble, the glossiness of the A side will not reach the desired level. Therefore, in the present invention, it is necessary for side A to satisfy the coating condition of 3.5 g/m2 or more.

However, an excessive amount of coating on side A will cause a rise in production costs, and it is undesirable to apply more than necessary, so the amount of coating on side A in the present invention is 3.5 g/m
A range of up to 6 g/m2 is preferred.

On the other hand, in the present invention, in order to give side A a property suitable for offset multicolor printing, the glossiness of side A is set to JIS -
20% or more is required as measured by P8142. 2
This is because if it is less than 0%, it is difficult to obtain beautiful color printing, which is the object of the present invention. Penetration-drying ink is normally used for the B side, but in both letterpress printing and offset printing, ink absorption speed and absorption power, or oil absorption, are required, and if these requirements are not met, the ink will semi-dry on the paper surface. If left in a dirty condition, dirt problems may occur due to set-off or rub-off. To solve this problem, it is better not to coat the B side.

The set-off value is generally used as an index to judge ink smearing, and it indicates the degree to which the printed surface smears the unprinted surface when printing with penetrating dry ink. Courser density value calculated from the light reflectance of the ink transferred from the printed surface to the non-printed surface using the densitometer Courser 61J, which is based on a new computer system developed by Courser Corporation in Tosas. It refers to
The causer density d is expressed as d=Iog−where R: reflectance.

Table 1 shows the relationship between causer density and reflectance.

Table 1 In the case of newsprint that does not cause problems when using normal penetrating drying inks, the set-off value is in the range of 0.22 to 0.28, and the three-sided set-off value of the present invention is also 0.28. Must be 28 or less. If the set-off value is 0.28 or more, the absorption of ink into the paper is slow, so the ink on the printing surface is transferred to the impression cylinder of the printing press, resulting in ``stains'' and the printing surface becoming slightly misaligned. This is not preferred in the present invention because it causes such trouble.

In this way, it is very important to reduce the set-off value of the B side of the present invention and increase the ink absorbency when using a penetrating drying type ink. Tree 8 One of the preferred methods of accelerating the absorption of ink on the B side of coated paper according to the invention is to reduce the nip pressure when performing polishing treatment with a super caloner, etc. to suppress the increase in density of coated paper. It is possible to do so. In this method, especially B
By selectively suppressing the increase in density only on the surface side, ink absorption is accelerated.

The purpose of this is, for example, when using a supercalender as a polishing device, so that side A of the coated paper according to the invention contacts the metal roll (delt roll) of the supercalender more often, and vice versa. The B side can be achieved so that the number of times of contact with the metal roll is eliminated or significantly reduced, that is, by bypassing and passing the paper without using all the stages of the super calender.

Furthermore, when paper is passed by bypass, it is better to use the upper roll for top feed (see Figures 1 and 2b) than to use the lower roll for bottom feed (see Figures 1 and 2a). )
It is possible to reduce the density on the B side. The reason for this is that the amount of the roll's own weight 9 affects the roll nip surface.

In the present invention, it is an essential requirement that the glossiness of the A side be 20% or more, so even if it is attempted to suppress the increase in density of the B side due to such processing, there are naturally restrictions on the supercalender processing conditions. , and the total nip pressure varies depending on the type of polishing equipment used, but with the super calender, 160 to 500 kg/c with 3 nip processing.
m range, 1200 kg with 12 stages and 11 nips
/ cm, it is possible to provide the A side with the minimum necessary gloss while preventing an increase in the density of the B side, thereby minimizing the deterioration of set-off.

(Example) The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited to these. still,
All parts and percentages used in the present invention are by weight.

Example 1 The pulp composition constituting the base paper is NBKP0 (680 gloss C, S, Ii) 30%, TMP
(100m1ICOS, F) 20%, RGP
(100 C, S, F) 30%, GP (65 Gloss C,
S, F) To the pulp consisting of 20%, talc for internal addition was added so that the ash content in the base paper was 7%, and cationized starch (manufactured by Tamago National Co., Ltd.) was added as an internal paper strength enhancer.
K) 3210) at 1.0% per pulp, sizing agent (5PG manufactured by Arayo Kagaku Co., Ltd.) at 0.3%, sulfuric acid band at 1.0%
% was added to produce paper with an absolute dry basis weight of 38.5 g/m 2 (referred to as base paper A) using a paper machine capable of producing medium-quality paper, gravure printing paper, and newsprint.

On the other hand, the coated tissue for coated paper uses kaolin as a pigment (USA [INIVBR3B TANKS, formerly manufactured by PS Co., Ltd., AMAZ
ON88), 25 parts of calcium carbonate (KS-2100-2, manufactured by Dowa Calfin Co., Ltd.), and sodium polyacrylate (manufactured by Toagosei Co., Ltd.) as a dispersant per 100 parts of pigment.
Added 0.2 part of Aron T-40), solid content concentration 70%
After adding water as much as possible and dispersing with a high-speed stirring derrick, 1. Carboxy-modified styrene-butadiene copolymer latex (manufactured by Japan Synthetic Rubber Co., Ltd., T-2045F) was added as an adhesive.
12 parts of and 4 parts of oxidized starch (Tamako Ace A manufactured by Tamago Cornstarch Co., Ltd.) were added and mixed.

A coating composition having a solid content of about 55% was prepared by adding and mixing other chemicals per 100 parts of the pigment and adjusting the pH to 8.5 with a 5% caustic soda solution.

The coating solution was applied on-machine using a blade coater for 10 minutes.
00 m/min, one side (A side) of base paper A was coated with 5 g/m2, and the other side (B side) was left uncoated.

2 The coated paper was then subjected to supercander treatment under the following conditions. The super calender is manufactured by Quine Wafers.

Processing conditions Paper speed: 500 m/min.

Bottom nip pressure 180kg/Cm Total nip pressure 500kg/Cm Paper passing Lower 3 nips (See Figure 2a) Lower base paper output (See Figure 1) The total nip pressure is the cumulative total of the nip pressure of each roll applied to the paper. means.

Table 2 shows the results of physical property tests of the coated paper.

The glossiness of side A is 22.2%, and the setoff value of side B is 0.
No. 26, both printed surfaces were good.

Example 2 NBKP (560mff [:, S, F,) 30%,
PGW3 (75mg C,S,li,) 45%, TMP (
100mg C.

S, F, ) 25% ash content in the base paper is 7.
Paper with an absolute dry basis weight of 38.5 g/m2 was manufactured under the same conditions as in Example 1 except that talc for internal addition was added to
(referred to as base paper B). For coating on base paper B, the coating composition, coating method, and processing conditions with a super calender were the same as those in Example 1.

Table 2 shows the results of physical property tests of the coated paper.

The glossiness of side A is 23.4%, and the setoff value of side B is 0.
The difference between No. 22 and the one obtained in Example 1 was that PGW was used as the pulp composition and its ratio was increased, resulting in an even better offset printing paper.

Example 3 A coated paper was produced using the same pulp composition, paper making, and coating composition as in Example 2, except that the A-side coating amount was 3.5 g/m2 and the super calender treatment conditions were changed. .

The super calendar processing conditions are as follows 4 Met.

Paper speed: 350m/min.

Bottom nip pressure 180kg/cm Total nip pressure 1
200 kg/cm passing paper 12 stages 11 nips (top) (see Figures 1 and 2 C) Table 2 shows the results of the physical property tests of the coated paper.

The gloss level of side A is 20.8%, and the setoff value of side B is 0.
A good printed surface was obtained with No. 25.

Example 4 A coated paper was produced using the same pulp composition, paper making, and coating composition as in Example 2, except that the A-side coating amount was 6.0 g/m'' and the supercalender treatment conditions were changed.

The super calendar processing conditions are as follows5 Met.

Paper speed: 500m/min.

Bottom nip pressure 180kg/am total nip pressure
160 kg/cm passing paper, upper 3 nips (top out) (see Figures 1 and 2b) Table 2 shows the results of the physical property tests of the coated paper.

The glossiness of side A is 22.6%, and the setoff value of side B is 0.
No. 23, a good printing paper was obtained.

Example 5 A coated paper was produced using the same pulp composition, paper making, coating composition, and supercalender treatment conditions as in Example 2, except that the A-side coating amount was changed to 8.0 g/m2.

Table 2 shows the results of physical property tests of the coated paper.

6 The gloss of side A is 35.2%, and the setoff value of side B is 0.
．． A good offset printing paper was obtained with No. 24.

Comparative Example I The pulp composition, paper making, coating composition, coating amount, coating method, and supercalender treatment conditions were the same as in Example 2, except that the coating amount on side A was 3.0 g/m2. Manufactured paper.

Table 2 shows the results of physical property tests of the coated paper.

The gloss level of side A is 17.6%, and the setoff value of side B is 0.
21, and the penetrating dry ink printing on the B side was good, but the printability on the A side was not satisfactory.

Comparative Example 2 Coating amount on side A: 3.0 g/m2.8 coating amount: Og/m
A coated paper was produced in the same manner as in Example 2 except that the super calender treatment conditions were changed as described below.

Super calendar processing conditions Paper speed 3 5 0 rn/m
in.

7 Bottom nip pressure 180kg/cm Total nip pressure 1
200 kg/cm paper passing through 12 stages and 11 nips (top-out) (see Figures 1 and 2 C) Table 2 shows the results of physical property tests of the coated paper.

The gloss of side A is 19.1%, and the setoff value of side B is 0.
It was 25. Although the printing with the penetrating drying ink on the B side was good, the gloss on the A side was inadequate.

Comparative Example 3 Coating amount on side A was 5.0 g/m', and coating amount on side B was 5.0 g.
A coated paper was produced using the same pulp composition, paper making, coating composition, coating method, and super calender treatment conditions as in Example 2, except that the paper composition was changed so that the coating composition was changed so that the amount of paper was 20%.

Table 2 shows the results of physical property tests of the coated paper.

The gloss level of side A is 25.0%, and the setoff value of side B is 0.
40, the A side was good, but the B side was unsuitable for printing with penetrating drying ink.

8 Comparative Example 4 A paper coated with no coating composition on either side A or B was subjected to supercalender treatment under the following conditions. pulp composition,
The paper making process was the same as in Example 2.

Super calendar processing conditions Paper speed 350 m/mi
mouth.

Bottom nip pressure 180kg/CI Total nip pressure 1
200 kg/cm passing paper 12 stages 11 nips (top) (see Figures 1 and 2C) Table 2 shows the results of physical property tests of the coated paper.

The gloss level of side A is 9.2%, and the setoff value of side B is 0.
No. 24, the B side was good, but the A side had unsuitable gloss.

The quality and physical property test results listed in Table 2 were evaluated based on the following test methods.

Test method (1) Glossiness Measured using a Murakami gloss meter. The measurement is performed at an incident angle of 75°, and the sample is irradiated with light and the reflected light is received by a light receiver depending on the gloss of the sample. The higher the number, the better the glossiness.

(2) Use newspaper off-print ink (TV = 3~
1 minute after printing using a penetrating drying type offset ink (equivalent to 4), this printed surface has a surface area of 157 g/m2 and a whiteness of 82.
Commercially available A with ±1.5%, gloss level 62±8%, thickness 132μ
The transfer of ink to commercially available A2 coated paper when the two coated papers were overlapped and pressed together with a pressure with a nip width of 10 mm was measured using a courser densitometer, and the value was taken as the set-off value. The smaller the number, the better.

(Effects of the Invention) 1 The present invention provides one side (side A) of base paper containing mechanical pulp.
A coating composition containing a pigment was applied to one side, the other side (Side B) was left uncoated, and the coating was applied under the conditions of the polishing device.
The A side of the coated paper was selected and processed to increase its gloss, so the A side of the coated paper is suitable for offset multicolor printing, and the uncoated B side opposite to the A side is suitable for printing with penetrating drying inks. Because of this, high-speed rotary presses such as printing equipment for newspaper printing can print monochrome on one side and high-quality multicolor printing on the other side.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the state of roll feeding in the super calender process used in the present invention, Fig. 2a is a diagram showing the state of paper passing through the lower three nips in the super calender process, and Fig. 2b is the same. FIG. 2C is a diagram showing a state in which paper is passed through the three nips in the upper stage, and FIG. 2C is a diagram showing a state in which paper is passed through all stages. 2

Claims (1)

[Claims] A bone-dry coating amount of 3.5 g of the pigment coating composition is applied only to side A of base paper containing at least one type of mechanical pulp such as pressurized stone ground pulp, stone ground pulp, refiner ground pulp, and thermomechanical pulp. /m^
Coat so that it is 2 or more, and the A side is JIS-P8142.
The gloss level as measured by the printer should be 20% or more, and the B side should be printed with a penetrating drying type offset ink of newspaper off-circle ink (TV = 3 to 4 equivalent) using an RI printing machine, and the printing density should be 1.0 using a courser densitometer. After 1 minute of printing at ±0.1, commercially available A_2 coated paper with a whiteness of 82 ± 1.5% and a gloss of 62 ± 8% was layered on the printed surface and pressed with a pressure of a nip width of 10 mm. At the time, the ink transfer to the commercially available A_2 coated paper is polished so that the value (set-off value) measured with a courser densitometer is 0.28 or less, and the A side has properties suitable for heat set-off printing. A method for producing coated paper for offset use, characterized in that the B side has properties suitable for printing using penetrating drying ink.